Aug. 4 – Given current warming trends, the average annual temperature in Acadia National Park could rise by as much as 8 degrees Fahrenheit and the average number of high-temperature days could increase by 24 days per year by 2050, according to a new report from the National Park Service.
But it’s the precipitation outlook that worries park managers the most. The report’s authors can imagine two very different futures for Acadia: one that’s hot and dry, where annual rainfall drops by 2 inches, and another that’s hot and sticky, where annual rainfall increases by 8 inches.
“Eight degrees would be a huge increase, but even if that happens, we’d still be pretty comfortable compared to other parks because it’s Maine,” said Abe Miller-Rushing, Acadia’s science director. “Heavy rains, storms, sea level rise. Those are our biggest climate threats. They’re causing so much damage.”
Under the more optimistic “hot and dry” scenario, which assumes that global combustion of heat-trapping fossil fuels is drastically reduced, temperatures would rise by 2 degrees and rainfall would fall by 3.2 percent by 2050. The park would then gain an additional nine days (instead of 24) when daily maximum temperatures reach 86 degrees.
To put this in context, historically warm years in Acadia would average out under the best-case scenario. The average temperatures projected under the worst-case scenario, meanwhile, would be warmer than any year in Acadia, at least in recent history.
The report, released last week by the National Park Service’s climate change response program, emphasizes the importance of adaptation planning. Its authors urged park managers to consider both scenarios as they develop strategies to protect Acadia’s natural and cultural resources.
The park’s recent temperature data suggests that the best-case scenario is already out of reach. Although the weather fluctuates, Acadia’s average annual temperature has risen by half a degree in the past three years alone — 25 percent of the projected 2-degree increase.
Miller-Rushing said Acadia is taking climate change into account, but that the National Park Service, like most conservation organizations, struggles to manage change because it goes against the conservation and restoration mindset.
“We’ve always thought about the past, about returning ecosystems to their pre-European state,” he said. “Now we know that’s not possible. One in six plant species here when Acadia was settled 100 years ago is gone. So we realize we can’t keep it the way it was.”
Acadia has a track record of pioneering change in the National Park Service, even if it wasn’t necessarily in response to climate change. To help ease congestion, Acadia operates a bus shuttle system, a reservation system for popular attractions, and now an online campground and car alert system.
According to the park service, Acadia National Park was the seventh most visited national park in 2023, when the forested area on the coast of Maine welcomed 3.9 million travelers.
Schoodic Institute, Acadia National Park’s nonprofit science organization that operates one of the park’s 18 research and learning centers, is helping managers prepare for that uncertain future through a series of grants and research projects in the park.
And the science is clear: change is already happening, says Nick Fisichelli, the institute’s president.
“Acadia is changing rapidly and we are seeing this happening in real time,” he said. “Climate change is no longer a 2050 or 2100 issue. It is a ‘here and now.’ Nature is dynamic and it is problematic to keep it as it was in the past.”
Schoodic’s role is to work with managers to produce the science that will inform park management under ever-changing circumstances, Fisichelli said. Given the pace of change, park managers can’t wait for the science to be done in isolation before taking action, he said.
And that stewardship must be transparent, Miller-Rushing said, with extensive public participation from local and indigenous communities. Together — Schoodic, Acadia, the public, the tribes — we must shift the conservation paradigm from protecting the past to promoting a better future, Fisichelli said.
For example, the park is working with scientists and tribal representatives to decide how to revegetate the 116-acre Great Meadow wetland. The park will remove invasive species, remove drainage ditches and old roadbeds, and replace an undersized culvert that sometimes left the wetland too dry and sometimes flooded.
The project will enhance the wetland’s natural function and the diversity of plant and animal species. It will reduce damage to park facilities that can occur during storms when floodwaters upstream of the culvert back up and flood the Sieur de Monts area, Miller-Rushing said.
Extreme temperatures can lead to infrastructure problems: they can cause accelerated wear and tear, put greater strain on electrical grids and cooling systems, buckle and crack roads, and require the park to build shade and cooling structures to protect visitors from the extreme heat.
Extreme precipitation can leave forests struggling, vulnerable to invasive species and wilting during wet conditions and susceptible to wildlife during droughts. The park’s signature coastal areas can be eroded or washed away by rising sea levels and storm surges, as this past winter demonstrated.
A half-mile stretch of the state highway that connects Southwest Harbor to the park’s Seawall Campground and the Wonderland and Ship Harbor trails repeatedly washed away during winter storms, leaving large piles of boulders on the crooked road. Officials considered closing the road but repaired and reopened it last month.
The park also decided to repair a 1,000-foot section of the scenic Ocean Path, a 4.5-mile (7.2-kilometer) trail that overlooks pink granite cliffs and connects the increasingly endangered Sand Beach to the ever-popular Thunder Hole on the east coast of Mount Desert Island.
Fixing Ocean Path was just one item on a growing list of storm repairs that exceeded the park’s $10 million annual budget in the spring, before rangers could access the more remote trails and assess their damage. Still, Ocean Path’s popularity made it a must-fix, a time to resist change.
“We can’t harden the entire coastline,” Miller-Rushing said. “In some areas, we have no choice but to accept it.”
Miller-Rushing uses the buzzwords of the National Park Service’s official response to climate change: the resist-accept-direct framework, or RAD for short. In some cases, such as Ocean Path or Seawall Road, a park can resist change by rebuilding.
In other cases, they might accept a freshwater marsh that becomes brackish and then salty due to sea level rise. Or in the case of Great Meadow, they might manage climate change through culvert replacement and selective planting. And in some cases, park managers are playing a waiting game.
The storms washed away about half of the dune system that separates Sand Beach from an inland wetland, Miller-Rushing said. The dunes will likely disappear in the coming years, washed away by a future storm. Without that buffer, the beach and wetland are at greater risk of storm erosion.
They may be letting the dune system go, but Sand Beach? It’s the park’s only sandy beach and one of its most popular attractions. While no decision has been made yet, that’s a debate — and a funding request — that will happen in the future.
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